He says "We are a Binance affiliate, we refer users via the opt-in trading widget on the new tab page, but autocomplete should not add any code."

Charitable interpretation: It is possible that he told the development team to add the affiliate code on the new tab page, and someone in the development team decided to add it to the autocomplete code as well, without him realising. I've certainly seen it happen when developers are told to do X and then they decide "oh since we are doing X we should do Y too". It isn't even always a bad thing, but sure sometimes it is.

Of course, the charitable interpretation could be wrong. Maybe he is actually being deceitful here. But, I prefer to assume the best of people rather than the worst.